Purine Flashcards
What is the structure of DNA?
DNA is a double-stranded molecule found in the nucleus of eukaryotic cells and the cytoplasm of prokaryotic cells.
What are the components of DNA?
Nucleotides, nitrogenous bases, and phosphate group.
What are the building blocks of DNA?
Nucleotides.
What are the components of a nucleotide?
Phosphate group, sugar (deoxyribose), and nitrogenous base.
Name the purines found in DNA.
- Adenine (A) * Guanine (G)
Name the pyrimidines found in DNA.
- Cytosine (C) * Thymine (T) * Uracil (U)
What is the base pairing rule in DNA?
A pairs with T, and C pairs with G.
What is the difference between a nucleotide and a nucleoside?
Nucleotide: Base + Sugar + Phosphate group; Nucleoside: Base + Sugar (no phosphate group).
What is DNA methylation?
Addition of a methyl group to cytosine bases, often in CG-rich regions (CpG islands).
What is the effect of DNA methylation on gene transcription?
It inhibits gene transcription.
What is the significance of DNA methylation in epigenetics?
It plays a role in gene regulation.
Is DNA methylation common in bacteria?
Less common; it helps protect against viral infection.
What is chromatin?
Complex of DNA and proteins.
What are histones?
Proteins that help package DNA into nucleosomes.
What are nucleosomes?
Basic units of chromatin, consisting of DNA wrapped around a core of histone proteins.
